Thread rolling machine



D. M. WATKINS ETAL THREAD ROLLING MACHINE 'TSheeis-Sheet 1 Filed Nov.15, 1945 I53, I ll I a, v V

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Aug. 15, 1950 D. M. WATKINS ETAL 2,519,164 THREAD ROLLING MACHINE FiledNov. 153945 I I '7 Sheets-Sheet 2 Attorney 5 Aug; 15, 1950 D. M. WATKINSETAL THREAD ROLLING MACHINE 7 Sheets-Sheet' 5 Filed Nov. 15. 1945 Aug.15, 1950 p. M. WATKINS ET'AL 2,519,164

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m" N R m g- 1950 D. M. WATKINS ETAL THREAD ROLLING MACHINE '7Sheets-Sheet 7 Filed NOV. 15, 1945 b: a! wms 5 E I A ltorney 5 PatentedAug. 15, 1950 2,519,164 THREAD noLLIN-o MACHINE Douglas MackenzieWatkins, Halsteatl, and

,1 William Edgar .Dilke, London, England Application November 15, 1945,Serial No. 628,904 In Great Britain July 24, 1945 k 10 Claims. (tim s)This invention relates to the rolling of screw threads upo-n'blanks bymeans of pairs of hardened rolls having peripheral threads on theirsurfaces. In machines for this purpose, the blank is interposed betweenthe two rolls and the metal of the blank is displaced to formthrea'ds'of the desired depth and pitch without removal of metal.

In machines as at present constructed, either one roll advances towardthe other while the thread is rolled into the, blank, or the blank iscaused to pass laterally into and through the gap between the rollswhichare set at such a distance apart that a thread of the required formand depth is impressed upon theblank as it passes into and through thegap. In the latter case, controlled travel of the blank into and throughthe gap is provided by making one of the rolls slightly greater indiameter than the other, while driving both rolls at the same speedofrotation, in order that the difference in circumferential speed ofzthewlarger roll may control the movement of the blank into and past"the gap when the blank is .gripped bythe rolls, In such machines, theblank, after passing through the narrowest gaps between the rolls,continues to move away from the gap at the speed with which it entered,until it falls free of the rolls, but it is liable to be damaged bycontinuing contact with the threadsof the rolls and it is an object ofthe invention to avoid this. With this object in view, the invention isdesigned, to provide "for the rapid ejection of the (rolled blankimmediately after passing through the narrowestfportionor center of thegap by imparting a longitudinal movement'to one of! the rolls relativelyt'o theother whereby a rolled blank i automatically ejected by itsengagement with-the. threads n the, rolls. Other objects are toproyidefortheaccurate adjustment of the rolls and" their shafts, for variationof the settingof the rolls when operating upon blanks of differentsizes, for the feed of the blanks ,tothe gaps betweenthe rolls, 'and"forcontrol of allthe movements of the parts so that the operations may beas automatic as is desired. An ultimate object is to render the wholeoperation of the machine automatic so that blanks are introduced, rolledand ejected in regular sequence.

L TIA convenient'form ofthe machine for carrying the-invention intoeffect isillustrated in the accompanying drawings, inwhich:

Figure 1 lis.an end elevation, partly in section,

of the complete machine; 1 Figure 2 is a ,vertical sectionon the line11-11 of Figure l;

, Figure. 3' is. a plan viewv partly in section 011w,

the ,1ine"IIIIII ofIFig'ure 1; Figures lAland 4B, taken-together, show,on an enlarged scale, the principal operating parts'of "the, machine, insection on, the line lvlv of i ures; ,i

a worm 4}] in head 41.

,l:igure 5 shows the driving gear for the roll shafts in section on theline V-V of Figure 4B; Figure 6 is an end view, partly in section and onan enlarged scale, of the blank feeding and thread-forming mechanism;Figure 7 is a diagram of the electric and hydra'ulicf circuits used inthe control of the ma; ch n U l r Referring to the drawings, the machineshown has a base casting II] on which is carried an upper casting llsupporting the main operating parts. The base casting H] carries at oneend an electric motor 12, whose shaft carries a stepped pulley l 3driving, through belt 16, a stepped pulley M on shaft I5. This shaftdrives, through gearing in casing 1, a worm l3 meshing with worm wheel lSon upright shaft 20. The shaft 20' drives the two horizontal shafts2l'and ZZcarrying the rolls 23 and 24, respectively, for rolling thethreads into the blanks 25. As shown in Figure 5, the verticalshaft 20is supported in ball bearings, 26, .21, 28, 29 and 30, and has a worm'dlkeyed on it and driving worm wheel 32 on shaft 2|. As shaft 22 isadjustable up and down with respect to shaft 2|, the worm 33, drivingworm wheel 34 36 is carried by a slide 31, which works over dovetailedguide surfaces in a column 38, and can be adjusted in height by a handwheel 39, actuating This worm 4|] engages with worm wheel 4i, keyed to anut 43, which engages a heavy screw 42 whose lower end is secured to theslide 3?, as best seen in Figure 4A.

A long taper wedge 46, with a fine adjustment at 44 on the slide, asshown in dotted lines in this figure, enables any Slack to be taken upin the guide surfaces, the wedge being olampedafter adjustment by ascrew 45 engaging in a slot in the slide. The worm 4| and nut 43 arecarried .in a head 41 secured by bolts 48 to the top of column 38 ,andby bolts 49 to another column 50, both columns 38 and 59 being mountedon the casting H. The slide 3! is locked in its adjusted positions bybolts 5| extending through slots at 52 in the column 38.

Referring'to Figures 4A and 4B, the worm wheels 32 and 34 are bothsplined on their shafts ,2! and 22, respectively, and are mounted inball is supportedcby a roller bearing, its projecting end being carriedin another roller bearing 58 in secured by boltsifioi to asiaiei 3 Theshaft 2| is similarly supported in roller bearings 61 and 68, the latterof which is carried in a bracket 59 detachably secured by bolts to thecasting H. The object of using the detachable brackets 59 and 69 is togive access to the ends of the shafts 22 and 2| for changing thethreaded rolls 24 and 23 when threads of different sizes, forms andpitches are to be rolled in the blanks. The inner members of the rollerbearings 58 and 68 are held by nuts 65 and 15, respectively, formed withholes adapted to be engaged by a suitable tool to enable the bearings tobe released when the shaft ends are opened up for changing the rolls 24and 23. Each roll 23 and 24 is mounted on a taper sleeve, BI and I l,respectively, fitting on a taper 64 and M, respectively, on its shaft,and locked by a nut 62 and 12, respectively. The rolls are fixed ontheir sleeves by nuts 63 and I3. For rolling right-handed screw threads,the roll 2 is made slightly larger than the roll 23, generally fromten-thousandths of an inch to thirty-thousandths of an inch greater indiameter, so as to turn at a slightly greater surface speed forimparting the travel to the blanks 25 as they pass into the gap betweenthe rolls. A difference in diameter of about twenty-thousandths of aninch has been found suitable, but the amount varies with the depth ofthread to be rolled and the time required for rolling it and finishingit in the blanks. The rolls 24 and '23 are formed with multiple startthreads, having sa'y eight or ten starts for a coarse pitch, to thirtyor more starts for a fine pitch, depending on the sizes of the rolls,their length, and the thread to be formed. The rolls need only differfrom standard rolls hitherto used in thread-rolling machines in that oneroll is of slightly greater diameter than the other for the purposealready indicated.

Referring again to Figure 4B, it is seen that provision is made forimparting a small amount of longitudinal movement to the shaft 2|. Aball-bearing collar 76 connects the end of shaft 2| to a stub shaft Hwhich does not turn but is capable of imparting longitudinal motion toshaft 2| through the ball bearing collar. The shaft 11 and a threadedsleeve 18 fitting thereon are both keyed by a feather iii to the bracketat bolted to the end of the housing which surrounds the gear 32 and ballbearings 53. The bracket 80 carries a casting 8| which houses a wormwheel 82 formed as a nut to work on the threaded sleeve 18 and which isheld against longitudinal movement by the end of bracket Bil and ashoulder in casting 8|. The worm 83 gearing with wheel 82 is fixed on aspindle 84 provided with a milled adjusting head 85, Figures and 3, bymeans of which head the worm wheel 83 can be adjusted with accuracy forsetting the sleeve ZS which limits the movement of shaft 71, andtherefore of shaft 2|, towards the right in Figure 4B. The shafts 2! and'11 can still be moved toward the left, however, and for this purpose apiston 86 is fixed on the end of the stub shaft 11, said piston workingin a cylinder the casting 8|, whose end is closed by a .plate 81. Twopipes, 88 and 89 for conveying liquid under pressure, are connected tosaid cylinder at opposite ends thereof. When a threadrolling operationbegins, pressure is applied through pipe 88 to the left side of .piston8-6 holding the collar 16, shaft H and shaft 2| in the tion in relationto the threads on roll '24 for commencing the rolling operation on ablank somewhat toward the right of the plane through the axes of therolls as seen in Figure 6. As the blank moves toward the gap, therelative position will change slightly, and the fluid pressure on theleft hand face of piston 86 is therefore relieved as soon as the threadson the rolls have gripped the blank effectively, thus allowing the shaft2| to shift slightly toward the left. The thread-rolling operation iscomplete when the blank is in the central position of Figure 6, andafter a few turns of the blank in that position, it is polished andready for ejection. This is effected by applying fluid pressure throughpipe 89 to the right hand end of piston 86, causing the shaft 2| to makea short axial movement toward the left in Figures 4A and eB, thismovement being permitted by the splines sliding through worm wheel 32and by the inner members of the roller bearings 5i and 58 which are freeto move in that direction. The relative movement between the two rolls23 and 24 exerts a pressure on the flanks of the threads rolled on theblank, the effect of which is to expel the blank instantly. The expelledblank rolls over the surface of the lower roll 23 and over the adjustable tray 98 which delivers it through a slot in the column 38.There are, in fact, two trays 90 and 9|, which are separatelyadjustable, the tray 9| supporting the part of the blank whi .1 projectsbeyond the ends of the rolls and which may be the head or other part ofa screw.

The blanks are fed down a chute 92 provided at its lower or dischargeend with spring blades 93 at the front of said chute and a gap at theback of said chute through which a pusher 94 passes. This pusher movesforward toward the gap between the rolls 23 and 24, at first quickly andthen at a slower rate until th blank impelled by the pusher iseffectively gripped by the threads of the rolls, the pusher 94 havingadvanced to the position 94 shown in dotted lines in Figure 6. From thispoint onwards it is the difference in superficial speed of the upper andlower rolls which advances the blank into and just past the gap. Theblank would tend to remain too long at the gap and its thread might bespoiled if it were not expelled quickly from the gap, and thelongitudinal or axial movement of the lower roll 23 insures this rapidexpulsion. The chute '92 is adjustable and interchangeable with chutesof other sizes for blanks of different dimensions, being secured bybolts 95 engaging in slotted lugs 96.

The pusher is advanced by a piston 9! (Figure '7) in a cylinder I09, tothe end of which cylinder liquid is admitted under pressure by a port at99. In Figure '7, for simplicity, the piston is shown as being pressedback by a spring ||l6A acting against the liquid pressure, but in theactual machine, as seen in Figure 1, the pusher has a rack |0| engagingover 'a pinion 192 on a shaft Hi3, and this shaft extends forwardly, asseen in Figure 3, to carry another pinion I04, Figure 6, meshing with arack bar I05 below it. This rack bar M5 is shaped as a plunger to slidein a cylinder I91, its end being recessed to accommodate the spring 1116which bears against an abutment on a screw stem I09. This stem isadjustable in the end plate I08 and is locked in any setting by lock nutH0. The rack bar Hi5 normally bears at its other end against a screwstop I which is adjustable to limit the return movement of the pusher 94under the action of spring Hi6. In the example illustrated, the pinionI04 is, in

solenoid .149 leads through pipe 89 to the end of cylinder 9! fordisplacing the roll 23 longitudinally when fact, smaller-than thepi nionI02 (allowing for differences in scale between Figures 6 and 1), theratio being 1 2%, so that for say 1 inch movement of the rack bar I05toward the right in Figure 6, the pusher 94 moves 2 inches toward thegap between the rolls. This movement against' the resistance 'of springI06 is-efiected by liquid pressure acting upon the piston 91 in cylinderI00, whilethe pusher 94 is advanced at first quickly to feed a blank 25,and then slowly to push the blank into the gap between the rolls. Whenthe liquid pressure is relieved, the spring I06 returns the pusher 94 toits retracted position as shown'in Figure 6, whereupon a further blankfalls infrontof the pusher ready for the'next feed. i

As the size of the blanks 25 may vary, and the height 'of the centre ofthe gap between the rolls 23 and 24 is adjusted to correspond, so theheight at which the chute 92 is set and at which the pusher 94 operatesshould be adjustable. The chutes 92 can be made with their slots 96 atthe proper height for each, but the pusher requires raising to half theheight of the gap between the rolls23 and 24 so that it may be centredwith themiddle of the gap. This result is attained by mounting thecasting I I2, which contains the cylinders I00 and I01 together with thepusher and rack mechanism, sothat said casting can be raised and loweredin guides on the faceof the column 50, by means of a screw stem II3which works-in a screw socket in the casting II, andis adjusted by a barinserted in holes in a disc H4. The casting H2 is clamped in itsadjusted position by bolts II5 extending through slots in the column 50.A nozzle I I6 discharges cutting compound over the blank at the gapbetween the rolls 23and 24 when the machine is in operation. Thesequence of operations in the machine is controlled electrically throughelectromagnetic contactors which operate valves in a hydraulic system,and it will be most'convenient to describe the controlsystem mainly withreference to the diagram of Figure '7, although most of the partsreferred to can be seen in the different figures from '1' to 6, in theiractual positions. zThree-phasecurrent is supplied through terminalsi29to three-phase contactors I2I and I22, which contactors includeholding-on solenoids I28, I29 and I'30'respectively. The contactor "12Econtrols the circuit of motor I2 and contactor I22 controls the circuitof a motor I33 mounted on'top of an oil tank I34 in the base casting l0(Figure 1). Motor I33 drives 'two pumps I3I and I32 which draw oilthrough pipes I35 and I36yrespectively, from tank I34 and deliver itthrough pipes I31 and I38, respectively. The pump !3I delivers oilthrough a high pressure relief valve I39 to a four-way valve I 40, whilepipe I38 delivers oil through an adjustable pressurerelief valve I M toanother four-way valve I42. Valve I40 is controlled by two solenoids I43and I44, andv valve I42 is controlled by a single I45. One pressureoutlet from valve a rolled blank is to be ejected. The other pressureoutlet of valve I40 leads through pipenl46 to a mechanically operatedvalve I41, and through pipe I48 to a regulatable pressure valve !49whose adjusting disc I50, with a pointer and scale fprjfine setting, isseen in Figure 1. Both valves I41, and I49 lead to the inlet port 99 ofcylinder I00 whose piston 91 advances the pusher 94, Valve I41 allows .arelativelyjast flow; of -O11 which advances the pusher 94 rapidly at:first, until a cam surface at I5I depresses a roller I52 on the head ofa push rod I53 (Figure 1) which is guided in its vertical movement in alug beside cylinder I00. This push rod I53 has a screw coupling in it atI54 whereby. its length can be adjusted, and its lower end belowthecasting II carries a shoe I55 which bears on a roller I56 on theoperating stem of valve I41. The depression of: the stem of valve I41stops flow from left to right through this valve, leaving the oil to .bedelivered to the cylinder I00 only through valve I49, which valve I49 isset to give a much slower delivery for advancing the pusher 94 slowlywhile the blank 25 is being thrust into the gap and grippedby thethreads of rolls 23 and24. The

pusher .94 follows up, the blankas' it is gripped and as its metal isdisplacedby the rolls 23 and 24 until it is certain that the feed .willcontinue without assistance from the pusher, whereupon the pusherrecedes as described hereinafter. In Figure 'I, the cam I5I and rollerI52 are shown, but for simplicity the roller is shown as actuating thestem of valve I41 directly. The four-way valve I42 controlled by asolenoid I45 leads to pipe 88 and to the inner end of piston 86 incylinder 8! for admitting pressure .oil to keep the member 16 againstthe end of member 18 as seen in Figure 4B. v

The end of cylinder I00 is connected to a valve 151 with v a pressureadjustment at I58, this valve serving to operate a contact maker I59 inthe circuit of relay I21 whena certain pressure is exceeded in the headof cylinder I00. Each of the valves I39, I40, I4I, I42, I41, I49 and I51has a return to tank I34 indicated by an arrow head below the valve. Ineach case of valves I39, I4I, I41, I49 and l51, these returns are openedautomatically when a certain pressure is' exceeded, but the outlet totank at I60 on valve I40, and the outlets to tank I6I and I62 of valveI42, are positively controlled by, these valves. Several switches withstart and stop buttons are provided as shown in the contactor circuits.The

start button I63 and stop button I64 of contactor I2I, serverto startand stop the motor I2". Numeral I65, designates a reversing switch inthe motor circuit by which the motor I2 may be caused to rotate ineither direction. This re versing action is required to enable themachine to roll either right-handed or left-handed threads on the blanks'25. When left-handed threads are to be rolled, the large diameter'rollshould be on the lower shaft 2I nd the lower diameter roll on the uppershaft 22, so that the higher surface speed of the lower roll will thendetermine the. travel of the blank through the gap. In the normaloperation of rolling righthand threads, it is the upper roll 24 which isthe larger as already stated. Start button I66 and stop buttonI'617operating the contactor I22 control the circuit of motor I33 whichdrives the pumps I3I and I32. :T'he slide of pusher 94 carries an'adjustedhscrew pin I68 which operates'a releasebutton I69 in thecircuit of contactor I25, this button being of the spring-controlled:the switch mechanism I69 and I10, ismounted on a fixed cross bar I19,and theslide of the pusher 94 has a screw adjuster I80, the adjusted endof which abuts against the cross bar I19 in the position-to stop thePusher afte 11;

75 liaszoperated thel13115111 button: I 69i-lcz A -sflilll trablezscrewrpin 11h (Figure; B) swhich moves with thezcollar 1.6 .andupistonsilfi serves;to;o.perate.-,a stopbutton I12 the zcircuitof,.contactor=; 1. The; slide of. pusher 194;.carries-another adjustedscrew-pin 1.13., :Figureflta-whichsoperates a start buttonrill ttina-.parallelycircuiawith: a button l'lficfor operating contactor .I 25when the feed of blanksfrom chute. 92.:is-lto.-be automatic; Stantbutton 116 and-stop button I 1 'I contro1- thecircuit ofcontactor I25when the.. cycle of operae tions in rolling threads .onblankstis. tmbe'controlled-for one blank at atime instead- -of being automatic -Theelectric connections and contactors are conveniently situated on theback of a door I8I in the basecasting I0, Figure 1, with the start andstop buttdnsISS and I64 for the motor I2 on the front, and also thebuttons I66 and I61 for; the pump I33, and buttons I16 and. I11 forcontactor I25. Button I16 is used for starting, and IT! for stopping,the feed of blanks 25, Whether the supply is automatic or not.

I It will be convenient now to trace out the operation of the circuits,contactors and valves fora working cycle. The start buttons I63 and I66are depressed to start the motors I2 and I33, respectively, inoperation, so thatthe rolls 23 and 24 are rotating at their correctspeeds, and the pumps I34 and 132- are circulating oil, while all thecontactors exceptI2I and I22 are de' energised. Theoil from pump I3I isreturned'at low pressure to tank I34 through relief valve I39 and portI69 of valve I46 whichis then open. Dhe oil from pum I32 passes viarelief valve I4I', and'four-way valve'l42'to pipe 88 and the inner faceof piston 66, so maintaining a pressure sufficient to hold the collar 16against member 18, in which position the roll 23' is held firmly in itsright-hand "end position ready to start rolling the threadinto a-blank25. Excess oil from pump I32 returns to tank I34 via return outlet ofrelief valve I45; When the start button I16 is pressed, the contactorI25 is energised, causing solenoid I43 to be energised and setting thefourway-valve I43 in "the position in which oil from pump I3I and reliefvalve I39 passes through pipe I46, valve-I41 and'port 99to cylinder I00,pressing piston 91 and pusher 94 toward the left in the diagram. Thepusher takes forward a blank -25 and moves rapidly up to the point wherethe blank is about to' touch rolls 23 and 24. At this stage, the camI"5I presses down roller I52 and closes the valve I41; through valveI'49'which is set to"give a slow delivery of oil, still to the sameport" 99, advancing the pusher 9'4 slowly but with a" substantialpressurebehind it, sufficient to force the blank between the threads ofthe rolls23 and 24, and to start the rolling of the'threads into theblank. The rolls nowgrip the blank between them and move it forward dueto the slightly higher peripheral speed of roll 24, causing it'to moveup 'to the central'plane-of the roll axes. Before this occurs,however,"the oil pressure in cylinder I00 will have risen rapidly as theresistance to fortact I59 andenergise contactor I21f'which, in

turn, energises solenoid I45; This solenoid moves valve I42 to aposition in which the inner face of piston 86 isopen 'through'pipe 88and return 'port .1 62-to the tank I34, while the oilreacliing valve Theoil now passes 1.4.2 viareli va1v .LiSslBHll-QQQfiQslih tan thr u r urnn r .I ero .23 ienow-fre'e o-.adiustiitselfr neitud ne rkeep-:itstthreads in e re e a em nt with t e-it eads be n rolled in;the'blank as this latter: passesdntmthe plane fi r ll c- The pusher .94continues; to movewforward even after. thegblank is grippedby the rolls,until screw llid pushes button ,-I.69.. thus..,breaking .the.,circuit ofcontactor elzi and closing, at I10, the circuit of contactor I26.The-s01en0id'l43 isthfusrdeenergisedand solenoid I I44: is energised-,5gmoving valve I lI'lv to a position in which pressure oil is deliveredthrough pipe {8,9, tfo the outer end of cylinder -8I thus moving, theroll 23 axially in the direction which causes the rolled blank to beejected over the tray 90. The oil from the other side of piston 86returns to tank I34 via port I62 of valve I42, and oil from cylinder I00returns to tank I34 'via valve I41 which allows free flow in the reversedirection as soon as port I60 of valve I40 connects pipe I46 to tank-I34, which occurs when solenoid I44 is energised.

As the piston-86 moves forward in cylinder BI, screw I1I-operates pushbutton I12 to break the circuit of contactor I26, thus causing solenoidI44 to be de-energised, and also de-energising contactor I21 andsolenoid I45, which allows valve I42 to returnto its starting position.All the solenoids-1 43, I44 and I45 are now de-energised. 'As the pusher94 moves back under the action of spring I66 (or 106A in the diagram,Figure-'7), the screw I13 operates push button I14 thus closing thecircuit of contactor I25 and so starting afresh cycle of operations, inwhich valve I46 is energised'by solenoid I43 causing oil to be deliveredby pipe I46, valve I41 and port 99 to the cylinder I00, and causing thepusher 94 to advance to thrust forward the next blank from the chute 92.It will" be realised, of-course, that the electric controls and thehydraulic operating circuits are only-an example of one-method ofoperating'the machine to roll threads into blanks, and that other meansof operationandcontrol might be provided which would effect the feed andpassage of a blank towards and through the gap between the rolls while athread is being impressed upon it. -It is essential in'all casesthat oneof the rolls should have'a slightly higher peripheral speed than theother "for determining the advance of a blank into and-across the gap,and this is most conveniently provided -for by making one roll slightly'larger'in diameter "than the other as already'explained. The machinecan be used 'for rolling threads-on any articles such as bolts, screws,taps and so forth which can be fed as blanks into th'emachine;

"We claim? l."A"mach'ine 'for'rollin'g screw threads into blankscomprising a pair of shafts and means for supporting them at apredetermined distance apart, a pairof thread rolling dies one slightlylarger in diameter than the other, means for m'oun'tingone'of Saidthreadrolling dies on each of said shafts, means for driving said shaftssimultaneously to move the surfaces of said thread rolling dies inopposite directions at their zone ofhearest approach with the surface ofthe larger ithread rolling die moving slightly faster than th surface'of theother threadrolling die, means for: feedihfiblanks 'to be threadedinto the gap between sa'id "thread rolling dies at one side of saiddies} nieans i for '"preven t ing longitudinal movement of one of saidshafts and of the thread rolling die mounted thereon, means for permit;ting longitudinal movement of the other of said shafts and of thethread-rolling. die mounted thereon, means for moving saidlast-mentioned shaft and die longitudinally"with respect tosaidfirst-mentioned shaft and dieyand means for timing-Zsuchi last-mentionedmovement to effect the sameimmediatelyupon thepompl'etion bfthe threadrolling operation when the blank is pass-'- ing through the narrowestportionof the gap between the thread rolling dies,=::such timed;slongitudinal movement rapidly ejecting the threaded blank laterally frombetween said dies. 7

2. A machine for rolling :screw thre'adsiinto blanks comprising a pairof opposed threa'd "roll-' ing" dies 'each formedwitlf multiple startthreads of the same pitch, one of said dies being slightly greater indiameter than the other, meansfor supporting said dies atarpredetermineddistance apart, means for rotating said opposed dies atthe same angular velocity and in opp'osite directions withthe' surfaceof the die {of greater diameter movingat a slightly""greater superficialspeed than" the 'surface "of' the other, meansdor feeding blanks to bet'hre'ad'ed towardsthe gap between said dies at the sid'eat whichth'e'f'surface of the die of greater diameter is approaching the gapbetween 'said diesfmeans for 'preventing longitudinal movem'entof-'one-of 'said dies, means for permittin'gloiigitudinal move- 'me'ntof'the other of said*dies; meansfor' oving said last-mentioned die"longitudinally with' refspect'to said first-'mentionedidie, andmeansio'r timing such last-mentioned movement to' effect thesarneimmediately uponthe completion of the 1 thread rolling operation whenthe blankis passing" through the narrowest portionb'fth'e gapbe tweenthe thread rolling dies, such' 'ti'med 'lo'ngitudinal movement rapidly"ejecting the"th'readed blankIaterallyfrom between said"dies"'f"3."A"machine foifi'blling screw threads into blanks comprising *apairof 'oppo'sedthread 'ifc'jllihg dies achiormed with mu1ti 1e'st rttnreads of "the same p'itchjdhebf said die's" being slightly greater indiameter' than'the otnernnearisrer movement of the last-mentioned dieafter the start of the thread rolling operation, means for moving saidlast-mentioned die longiti di iially with res ect to said firstm'entioned (lief-and *inean'sfor timing suchlast-mentioned movement r,

toefiect the: same immediately upon tidn 56f the? threadrtjIIin'gToperatiQn w n the blaiiki ispassing throug'h 'the narrowestportion 'ofithe-gap between the'thread rolling dies; suen timedlongitudinal movement rapidly ejecting ;A-mchine for "roll g screwthread s into blanks comprising a pair of opposed thread rolling dieseach formed with multiple start threads the threadedblank laterall frombetween said q; M I j greater :indiameter than the other, meansafo'rsupporting said dies at a predetermined distance apart, means forrotating said opposed dies at the same angular velocity and inoppositedirections with the surface of the die of greater diametermoving at a slightly greater superficial speed than thesurface of theother, means for feeding blanks to 'be threaded towards thdgap'betweensaiddies at the side at which the surface of the die of greater diameteris'approaching the gap betweensaid dies, means for preventinglongitudinalmovement of one of said dies, an abutment adjacent the otherof said dies adapted for engagement by said die to prevent longitudinalmovement of said die in one direction, hydraulic pressure means adaptedto maintain said lastmentioneddiein engagement with said abutment at thestart of the thread rolling operation, means for permitting release ofsaid hydraulic pressure and movement of said last-mentioned dieaway fromsaid abutment after the 'startof'thethread rolling operation, hydraulicpressure means for moving said last-mentioned die longitudinally withrespect to said first-"mentioned die and away from-said abutment andmeans 'for'timing the last mentioned movement to effect the same'by saidlast-mentioned hydraulic pressure inean's immediately uponthe completionof thethrea'd rolling "operation when the blank is passing througnthenarrowest portion of thegaifbetween the thread'rolling dies, such timed'longitudinal movement rapidly ejecting-the threaded blank laterally frombetween said dies? '5. A machine forrolling screw threads into blankscomprising a pair of spaced," parallel shaftspa pair "of opposed threadrolling""die's, means for securing oneof said dies on'e'aehbf saidshafts,"means supporting one 'of "said sliafts in a fixed positionlaterally, a' laterally-adjust able slide; means for supporting theother ofsa i d shafts-on said slide, locking means for fixing said slideina position of lateral adjustment determiningthe'gap between said'dies,means for driving said shafts simultaneously to move the"surfa'c :eofthe diesmounted thereon in opposite'dir'ee tions; one of saidthreadrolling dies being slightly greater in "diameter than the other,rneans'"for feeding blanks to be'threa'ded toward the gap between saiddies at the side thereof where the surface of the larger'of said dies isapproaching the gap between said diesjmeans for preventing longitudinalmovement of oneof said shafts and of the thread rolling die mountedthereon, mean forfperm'itting longitudinal movement "of'th'e other ofsaid shafts and of the thread rolling d ie mounted thereon, means'formoving said lastmentioned shaft anddi'e" longitudinally with "re; spect-to said first-mentioned shaft and di'ef means forti'mingsuch-last-mentiohed movement to effect'the same immediately upon *thecompile-'- tion "of the thread rollin'g operation when the blank :is.passing through the narrowest portion ofthe" gap between the dies, 'suchtimed longitu ,dinalrmovement"rapidly ejecting the threaded blanklaterally from between said dies; "i "6.-A machine forrollingscrewthreads into ,blankscomprising a pair of spaced; parallelshafts and power operatingmeans therefor, a'pairof thread-rolling diesone slightly larger in di meter than the other, means for 'securingfo e0 id dies on each of said shafts, meansuppert g one of s'a'id' shafts"in' a nxd pesitieii*iaterain,

means for adjusting the other of said shafts laterally and for lockingit in its position of adjustof the same pitch, one of said dies beingslightly ment to thereby determine the gap between said ll dies, apusher, means for guiding said pusher in its movement towards the gapbetween said dies, means for feeding blanks in front of said pusher,hydraulic operating means for said pusher, means for preventinglongitudinal movement of one of said shafts and of the die mountedthereon, means permitting longitudinal movement of the other of saidshafts and 'of the die mounted thereon, hydraulic operating means formoving the last-mentioned shaft and die longitudinally with respect tothe first-mentioned shaft and die, controlling valves for both of saidhydraulic op erating means, and means for effecting timed op-- erationof said valves to advance and withdraw said pusher, and to subsequentlyeffect longitu= dinal movement of said last m'ention'ed shaft and die bysaid hydraulic means immediately upon the completion of the threadrolling operation when the blank is passing through the narrowestportion of the gap between the thread rolling dies,

such timed longitudinal movement rapidly eje'ct= ing the threaded bla'nklaterally from between blanks comprising a pair of spaced, parallelshafts, a pair of thread rolling dies, means securing said dies inopposed relation on said shafts, driving mechanism adapted to rotatesaid shafts of rotation, means for adjustably supporting said shafts andfor locking them in fixed position latterally to determine the -width ofthe gap between the dies on said shafts, means for feeding blanks to bethreaded toward the gap between said dies at one side of said dies,means for preventing longitudinal movement or one of said shafts and ofthe die mounted thereon, means for permitting longitudinal movement ofthe other of said shafts and of the "die mounted thereon, means formoving said last mentioned shaft and 'die longitudinally with respect tosaid first-mentioned shaft and die, and means for timing "suchlast-mentioned movement to effect the same im'- mediately upon thecompletion 'of the thread rolling operation when the blank is passingthrough the narrowest portion of the ga between the thread rolling dies,su'ch timed longitudinal movement rapidly ejecting the threaded blanklater= ally from between said dies.

8. A machine for rolling screw threads into blanks comprising a pair ofspaced, parallel thread rolling dies, means for supporting said dies infixed relation laterally to determine the gap between said dies, meansfor simultaneously ro= tatlng said dies, means for feeding a blank to bethreaded toward the gap between said dies at one side thereof, means forpreventing longitudinal movement 'of one of said dies, means permittinglongitudinal movement or the other of said dies, and automatic mechanismadapted to sequen tiall-y operate said blank feeding means for advancinga blank toward the gapbetWeen said d'ies, then to withdraw said blankfeeding means, and finally to move said last-mentioned dielongitudinally with respect to said first-mentioned die, saidlongitudinal movement of said last-mentioned die being effectedimmediately upon 'the completion of the thread rolling operation whenthe blank is passing through the narrowest por tion of the gap betweenthe thread rolling dies to rapidly eject the threaded blank laterallyfrom 70 between said dies.

9. A machine for rolling screw threads into blanks comprising a pair ofthread rolling dies and means for supporting the same at a predetermineddistance apart in parallelism, one of said dies being of slightlygreater diameter than 5 the other, means for simultaneously rotatingsaid dies, a pusher adjacent the "gap between said dies, means forfeeding blanks one at a time in front 'of said pusher, an hydraulicpiston and cylinder, means connecting said piston with said pusher,spring returning means for said piston, means for preventinglongitudinal movement of one of said dies, means for permittinglongitudinal movement of the other of said dies, hydraulic mechanism,means connecting said hydraulic mechanism with said last-mentioned dieto effect longitudinal movement of said die upon actuation of saidhydraulic mechanism, a plurality of hydraulic control valves andelectrical means of control therefor adapted to control the supply ofthe hydraulic fluid to said piston and cylinder and to said hydraulicmechanism in such sequence as to cause, first, the advance of saidpusher, then to permit of the return of said pusher by said springreturning means, then to cause longitudinal movement of saidlast-mentioned die, and then to return said last-mentioned die to itsstarting position.

10. A machine for rolling screw threads into blanks comprising a pair ofopposed thread rolling dies, means for supporting said dies at a pr'edetermined distance apart in parallelism, one of said dies being ofslightly greater diameter than the other, a pusher adjacent the gapbetween said dies, means for feeding blanks one at a time in front ofsaid pusher, means for advancing and returning said pusher, means forsimultaneously rotating said dies, means for preventing longitudinalmovement of one of said dies, means for permitting longitudinal movementof the other of said dies, means for moving said lastmentioned dielongitudinally with respect to the first-mentioned die, and automatictiming mechanism adapted to sequentially control the ad= v-ance andreturn of said pusher, and the longitudinal movement of saidlast-mentioned die with respect to said first-mentioned die after saidpusher has been advanced and returned, the movement of saidlast-mentioned die being effected immediately upon the completion of thethread rolling operation when the blank is passing through the narrowestportion of the gap between the dies and serving to rap-idly eject thethreaded blank laterally from between said dies.

DOUGLAS MACKENZIE WATKINS. WILLIAM EDGAR, DILKEt.

REFERENCES men The renewin references are of record in the "file of thispat'ent' z 6 ammo seams PATENTS Number Name Date 1 ,551,591 Thomas Sept.1, 1925 2,182,906 Unke Dec. 12, 1939 65 2,257,234 Gould lie-11111-4Sept. 30, 1941 2,257,253 Wemhoner 'et al-. Sept. 30, 1941 2,448,217Batchelder Apr. 1, 1947 2,422,849 Plagemann 1- June 24-, 1947 NumberCountry Date I 370,773 Great Britain au e; Apr. 14, 1932

